HOUSTON, TX (CNN) -- A Houston family is going to need a lot of diapers.

Tressa and Manuel Montalvo are the proud parents of two sets of identical twins.

The four boys, who were conceived without fertility drugs, were born on Valentine's Day.

Tressa says they decided to have a little fun naming the newest members of the family. She says, "The names of the baby we just decided it would be easier for the family to keep up with the order that they were born, so we decided to stay with the a, b, c, d theme and our 2-year-old son being named memphis we thought of let's get something maybe like a little vegas theme going on and we decided to go with ace, blaine, cash and dylan."

The babies were born at 32-weeks and are all progressing well.

Doctors say the chance of having two sets of identical twins is about one in 70-million.